1. Field of the Invention
The present invention relates to an apparatus and method for controlling a power saving mode of a power supply.
2. Description of the Conventional Art
A conventional apparatus for controlling a power saving mode of a power supply is automatically switched to a power saving mode to minimize the power consumption of a power supply when a power saving mode key input signal is externally applied or a predetermined time has elapsed since alternating current(AC) power was supplied but the loads do not consume the AC power. Also, when the power supply is in the power saving mode, a backup capacitor of a backup unit provides power to a key input signal input unit and a microcomputer of the power saving mode controlling apparatus to detect the power supply operation key input signal.
FIG. 1 is a schematic block diagram illustrating a conventional switching mode power supply (SMPS) developed by the inventors of the subject application and disclosed in application Ser. No. 09/373,075, filed Aug. 11, 1999; and hereby incorporated by reference in its entirety. As shown, the SMPS includes a power supply circuit unit 124 and a controlling unit 122.
As shown therein, the power supply circuit unit 124 includes an input filter unit 101 receiving AC power from an AC power source and reducing noise included in the AC power; a rectifying and smoothing unit 102 rectifying and smoothing the noise free AC power; a switching device Q1 receiving a predetermined control signal from first and second signal feedback units 107 and 108 and switching on/off a transformer 104, which is to be later described; a snubber 103 eliminating switching noises which are generated in accordance with the switching on/off operation of the switching device Q1; a transformer 104 receiving DC (direct current) power outputted from the rectifying and smoothing unit 102 and transforming energy from a primary terminal to secondary terminals of the transformer 104 in accordance with an on/off operation of the switching device Q1, for thereby inducing a plurality of AC voltages; a first rectifying and smoothing unit 105 inputting the AC voltages which are induced at the secondary terminals of the transformer 104, rectifying and smoothing the AC voltages and outputting a plurality of DC voltages; a switching unit 109 receiving the DC voltages and outputting DC voltages Vo1, Vo2, . . . , VoN to loads (not shown) in accordance with the control of a microcomputer 110; a second rectifying and smoothing unit 105-1 inputting AC power, which was generated from an auxiliary terminal of the transformer 104, and outputting a DC voltage; and a driving control unit 106 receiving the DC voltage outputted from the second rectifying and smoothing unit 105-1 and control signals outputted from a control unit, which will be later described, and controlling the switching on/off operation of the switching device Q1.
Further, the control unit 122 of the conventional SMPS includes a microcomputer 110 controlling the system based in part on receiving key input signals such as from a power supply button 120; a timer 111 generating and outputting a timing signal to the microcomputer 110; a multiplexer 114 supplying either a high or low frequency signal from respective high and low frequency oscillators 116 and 118 to the microcomputer 110 and the timer 111; a backup unit 112 charged by receiving one of the DC voltages outputted from the rectifying and smoothing unit 105 and supplying power to the microcomputer 110 in the power saving mode; the first signal feedback unit 107 providing DC power to the driving control unit 106; and the second signal feedback unit 108 controlling an operation of the driving control unit 106 in accordance with a control signal outputted from the microcomputer 110 in the power saving mode. Wherein the first and second signal feedback units 107 and 108, respectively, are constituted of a photocoupler PC1, a switching device Q2 (e.g., a transistor), and resistors R3, R4.
The operation of the conventional SMPS will be described in detail with the accompanying drawings.
When it is in a normal mode, where the loads consume power and AC power is inputted to the input filter unit 101 from AC source power, the input filter unit 101 eliminates the noises included in the AC power and outputs the noise free AC power to the rectifying and smoothing unit 102. Then, the rectifying and smoothing unit 102 rectifies and smoothes the noise free AC power supply and outputs a DC voltage having a predetermined level to a primary terminal of the transformer 104 and the driving control unit 106.
Here, as the driving control unit 106 switches the switching device Q1 on and off, a plurality of AC voltages are induced to the secondary terminals of the transformer 104. Then the rectifying and smoothing unit 105 receives, rectifies and smoothes the induced AC voltages; thereby outputting DC voltages to the switching unit 109, which outputs the DC voltages Vo1, Vo2, . . . , VoN to the loads (not shown).
In the above-described normal mode, the microcomputer 110, which receives one of the DC voltages outputted from the rectifying and smoothing unit 105, controls the switching unit 109 so that it provides matching power to the loads. During the normal mode, the microcomputer 110 instructs the multiplexer 114 to output the high frequency signal so that the microcomputer 110 operates at the high frequency clock from the timer 111. Also, the backup unit 112 receives the DC power and charges a backup capacitor C3, for providing the charged power to the microcomputer 110 in the power saving mode.
When the power supply is in the normal mode, in which the loads consume the power, and a user inputs a power saving mode key input signal or a predetermined period of no power consumption has elapsed, the microcomputer 110 outputs a control signal having a predetermined duty to a photodiode PD of the photocoupler PC1 in the second signal feedback unit 108 through a resistor R2. When the photodiode PD and a phototransistor PT in the photocoupler PC1 are operated, the switching device Q2 outputs a control signal to the driving control unit 106, and, accordingly, the driving control unit 106 is controlled. Here, when the second signal feedback unit 108 is switched on, the driving control unit 106 receives a ground level signal, thereby stopping the switching operation of the switching device Q1 and stopping the operation of the transformer 104. Accordingly, the SMPS enters into a power saving mode.
When the transformer 104 is stopped and no voltages are induced in the secondary terminals of the transformer 104, that is when the SMPS is in the power saving mode, the backup unit 112 supplies a backup power to the microcomputer 110. Also, the microcomputer 110 causes the multiplexer 114 to output the low frequency signal so that the microcomputer 110 operates at a low frequency clock signal such as 32 kHz during the time when the transformer 104 does not operate.
When the power supply is in the power saving mode under the above-mentioned conditions, if a power supply operation key input signal is inputted to the power supply via the power supply button 120, the power supply immediately supplies the power to the loads.
FIG. 2A illustrates a remote controller (R/C) key input signal supplied to the conventional SMPS. The R/C key input signal includes a full code and a continuous code. The full code consists of a header and data, and the consecutive code indicates that a remote controller key is continuously pressed. FIG. 2B illustrates the full code of FIG. 2A in detail, wherein a header or enable part is a low frequency signal having a high level D1 and a low level D2 for a duration of 9.5 ms and 4.5 ms respectively, and a data or SMPS on part is a high frequency signal having a high level D3 and a low level D4 for a duration of 0.56 ms.
To detect the high frequency portion of the R/C key input signal, the microcomputer 110 must be driven at the high frequency clock (14 MHz), which consumes a considerable amount of power. When the microcomputer 110 is driven at the low frequency clock signal (32 KHz), the microcomputer 110 can not detect the R/C key input signal. Accordingly, the user has to manually press a power saving mode canceling key or power supply button 120 so that the SMPS provides power to the loads and the microcomputer 110 can detect R/C key input signals.
Accordingly, the present invention is directed to an apparatus for controlling a power saving mode in a power supply and a method thereof which obviate the problems and disadvantages in the conventional art.
An object of the present invention is to provide a method and apparatus for controlling a power saving mode in a power supply which converts a power saving mode of the power supply into a normal mode by a remote controller key input signal.
Another object of the present invention is to provide a method and apparatus for controlling a power saving mode in a power supply which detect a low frequency remote controller key input signal, cancel a power saving mode of the power supply and provides power to the loads.
Another object of the present invention is to provide a method and apparatus for controlling a power saving mode in a power supply which minimize power consumption during a power saving mode of the power supply, detect a low frequency remote controller key input signal, cancel a power saving mode of the power supply and provides power to the loads.
Another object of the present invention is to provide a method and apparatus for controlling a power saving mode in a power supply which minimize power consumption during a power saving mode of the power supply, detect a low frequency remote controller key input signal and operates a microcomputer with a high frequency clock signal.
These and other objects are achieved by providing an apparatus for controlling a power supply, which supplies power to loads, comprising: a low frequency clock generator generating a low frequency clock; a high frequency clock generator generating a high frequency clock; and a controller controlling operation of said power supply, operating at said low frequency clock in a first mode, receiving an input signal while in said first mode, determining if said input signal includes a predetermined portion while in said first mode, and switching to operation at said high frequency clock in a second mode if said input signal is determined to include said predetermined portion.
These and other objects are further achieved by providing a method for controlling a power supply, which supplies power to loads, comprising: operating a controller, which controls operation of said power supply, at a low frequency clock in a first mode; receiving an input signal while said controller operates in said first mode; determining if said input signal includes a predetermined portion while in said first mode; and switching operation of said controller to operation at a high frequency clock in a second mode if said input signal is determined to include said predetermined portion.